/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkDocument_DEFINED
#define SkDocument_DEFINED

#include "include/core/SkRefCnt.h"
#include "include/core/SkScalar.h"
#include "include/private/base/SkAPI.h"

class SkCanvas;
class SkWStream;
struct SkRect;

/* * SK_ScalarDefaultDPI is 72 dots per inch. */
static constexpr SkScalar SK_ScalarDefaultRasterDPI = 72.0f;

/* *
 * High-level API for creating a document-based canvas. To use..
 *
 * 1. Create a document, specifying a stream to store the output.
 * 2. For each "page" of content:
 * a. canvas = doc->beginPage(...)
 * b. draw_my_content(canvas);
 * c. doc->endPage();
 * 3. Close the document with doc->close().
 */
class SK_API SkDocument : public SkRefCnt {
public:
    /* *
     * Begin a new page for the document, returning the canvas that will draw
     * into the page. The document owns this canvas, and it will go out of
     * scope when endPage() or close() is called, or the document is deleted.
     * This will call endPage() if there is a currently active page.
     */
    SkCanvas *beginPage(SkScalar width, SkScalar height, const SkRect *content = nullptr);

    /* *
     * Call endPage() when the content for the current page has been drawn
     * (into the canvas returned by beginPage()). After this call the canvas
     * returned by beginPage() will be out-of-scope.
     */
    void endPage();

    /* *
     * Call close() when all pages have been drawn. This will close the file
     * or stream holding the document's contents. After close() the document
     * can no longer add new pages. Deleting the document will automatically
     * call close() if need be.
     */
    void close();

    /* *
     * Call abort() to stop producing the document immediately.
     * The stream output must be ignored, and should not be trusted.
     */
    void abort();

protected:
    SkDocument(SkWStream *);

    // note: subclasses must call close() in their destructor, as the base class
    // cannot do this for them.
    ~SkDocument() override;

    virtual SkCanvas *onBeginPage(SkScalar width, SkScalar height) = 0;
    virtual void onEndPage() = 0;
    virtual void onClose(SkWStream *) = 0;
    virtual void onAbort() = 0;

    // Allows subclasses to write to the stream as pages are written.
    SkWStream *getStream()
    {
        return fStream;
    }

    enum State { kBetweenPages_State, kInPage_State, kClosed_State };
    State getState() const
    {
        return fState;
    }

private:
    SkWStream *fStream;
    State fState;

    using INHERITED = SkRefCnt;
};

#endif
